1. Field of the Invention
The present invention relates to an impurity eliminating apparatus for eliminating impurities on a surface of a substrate, a film forming apparatus, and a film forming method.
2. Discussion of the Background
For example, in a process of semiconductor device fabrication, a process for forming a SOG (Spin-on-Glass) film has been performed for an interlayer insulating film or flattening so far. Specifically, a treatment solution called sauce made by dissolving SiOx in alcohol is supplied onto the surface of a substrate such as a semiconductor wafer (referred to as xe2x80x9ca waferxe2x80x9d hereinafter) and at the same time the substrate is spun to form a film by the treatment solution on the substrate surface. Thereafter, the substrate is heated twice to volatilize a solvent in the treatment solution and moreover baked. Thus, a predetermined interlayer insulating film is formed on the surface of a wafer and the substrate surface is flattened.
In a conventional process for forming a SOG film, after a wafer is taken out from a cassette storing wafers and carried to an apparatus in which a treatment solution is supplied and coated, for example, a spin coating apparatus so as to be coated with the treatment solution, the wafer is carried to a heating apparatus including a baking apparatus or a vertical type furnace where after predetermined heating treatment is performed for volatilization of a solvent and baking.
If the wafer itself taken from the cassette is, however, carried to the spin coating apparatus to be treated with the treatment solution as described above, so-called xe2x80x9cwettabilityxe2x80x9d is not satisfactory due to impurities such as organic substances adhering to the surface of the wafer and there is a possibility of causing problems in the subsequent fixing characteristic or fixing state of the SOG film. Besides, when the wafer W before forming the SOG film is in a state that the bottom corner portions of sidewalls 302 in a pattern 301 after being etched remain roundish as shown in FIG. 9, there is a possibility of exerting a bad influence on treatment for the wafer after having formed the SOG film, for example, formation of a conductive film, an oxidation insulating film, or the like.
Therefore, it is conceivable that the surface of a wafer is cleaned in advance, but in scrub cleansing or high-pressure jet cleaning used in a conventional film forming method such as a resist film forming method, organic substances on the wafer surface can not be fully eliminated and the aforementioned state that bottom corners remain roundish can not be solved. In addition, a process for drying is required thereafter, which is undesirable in respect of throughput.
An object of the present invention is to provide an apparatus and a method by which organic substances adhering to the surface of a substrate such as a wafer can be effectively eliminated when a SOG film is formed, for example, and such elimination of impurities can be easily and swiftly performed.
To solve the above problem, the first aspect of the present invention is an apparatus for eliminating impurities from a surface of a substrate including a mounting stand on which the substrate is mounted, an irradiating body for irradiating a predetermined wavelength of light to the substrate mounted on the mounting stand and generating ozone in space above the substrate surface, a casing for storing the irradiating body, a penetrating body disposed on a face opposite to the mounting stand in the casing for making the predetermined wavelength of light penetrate, and means for exhausting atmosphere in a space between the mounting stand and the casing.
The second aspect of the present invention is a film forming apparatus including an impurity eliminating apparatus provided with a mounting stand on which a substrate is mounted, an irradiating body for irradiating a predetermined wavelength of light to the substrate mounted on the mounting stand and generating ozone in space above the substrate surface, a casing for storing the irradiating body, a penetrating body disposed on a face opposite to the mounting stand in the casing for making the predetermined wavelength of light penetrate, and means for exhausting atmosphere in a space between the mounting stand and the casing, a film forming apparatus for supplying a predetermined treatment solution to the substrate to form a predetermined film on the substrate, and a carrier apparatus for carrying the substrate which completed the treatment in the impurity eliminating apparatus to the film forming apparatus.
The third aspect of the present invention is a film forming method including the steps of eliminating impurities on a surface of a substrate by means of an impurity eliminating apparatus provided with a mounting stand on which the substrate is mounted, an irradiating body for irradiating a predetermined wavelength of light to the substrate mounted on the mounting stand and generating ozone in space above the substrate surface, a casing for storing the irradiating body, a penetrating body disposed on a face opposite to the mounting stand in the casing for making the predetermined wavelength of light penetrate, and means for exhausting atmosphere in a space between the mounting stand and the casing, and supplying a predetermined treatment solution to the substrate to form a predetermined film on the substrate.
In the present invention, if an apparatus is disposed so that a space between a casing and a substrate will be full of air atmosphere, ozone is generated from oxygen in air between a penetrating body in the casing and the substrate by irradiation of light from an irradiating body. The generated ozone eliminates organic substances adhering to the substrate surface and solves the state that bottom corners of sidewalls in a pattern remain roundish. In addition, the above process is a so-called dry type eliminating process so that a succeeding drying process is unnecessary unlike a wet type. Accordingly, simple and swift elimination of impurities is possible. Besides, means for exhausting atmosphere in the space between the mounting stand and the casing is provided, whereby the generated ozone never diffuses to the surroundings and an in-line system in combination with other apparatus can be easily constructed. Naturally, an improvement in a contact angle on a surface of a substrate such as wafer can be realized, since impurities such as organic substances adhering to the substrate surface can be eliminated as described above.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. the objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.